Outdoor Surface Cleaning Blog

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Carpenter Bees in Your Wood Siding?

Carpenter bees are found throughout much of the southern and eastern United States. They resemble bumblebees except they have smooth and shiny bodies instead of hairy bodies. They also lack the pollen baskets on their legs that bumble bees have. They are not usually serious pests, although their tunnels can be damaging if the bees infest the wood annually to nest.


When carpenter bees nest they do so in wood and create tunnels in and out. The original entry hole is perfectly round and approximately a half inch in diameter. The tunnel turns at a right angle after penetrating the length of the bee’s body and runs across the grain of the wood.

Carpenter bees don’t usually create any structural damage despite their tunneling in wood, but that doesn’t make them any less annoying. Males are known to be aggressive when they are in their spring mating season, which may ruin your outdoor relaxation, but, don’t worry, the males can’t sting.

I for one don’t enjoy the thought of bees tunneling into my wood siding, deck, porch, fence, et cetera, but what can we do to prevent or treat them? Carpenter bees don’t tunnel into just any wooden surface. In general, they go after untreated, unfinished wood. Making sure that your wooden outdoor structures are finished and sealed is a great way to keep carpenter bees at bay. At Renew Crew, every time we clean and pressure wash a deck or any other wooden surface, we follow it up by protecting it. Our protective finish not only deters carpenter bees from tunneling, but also stops dirt and grime from settling in the surface.

If carpenter bees are already tunneling in your decks or fences, you’ll need an insecticide to get rid of them. The best method for bees is to use a dust type insecticide that can be shot into the tunnel holes. You’ll want to apply the dust in the spring months before the adults become active. If you wait, make sure to use the dust at night, reducing your risk of agitating the female bees. Angry female bees are known to sting to protect their nests.

So what do you do if you have tunnels in your wood that you would like to cover up? The first thing to do is to block and seal the nest holes so that future bees don’t find them (carpenter bees will use empty nests before creating new ones). Wood putty will work well to fill any holes. Once the deck is treated, the holes should be less noticeable. For instance, at Renew Crew, our protective finish will camouflage any preexisting holes and deter bees for the future!

If you have questions about maintaining wood structures, please contact your local Renew Crew office.